New species of duck-billed dinosaur may have originated in the North American south


Many dinosaurs are noted for their outsized proportions and, in some cases, oddball appearances. Now paleontologists are studying fossils from a previously undescribed species of duck-billed dino that exemplifies this. What’s even more fun about Aquilarhinus palimentus is that it’s a new genus and species of duck-billed dinosaur. It’s named for its aquiline snout and wide lower jaw that looks something like a pair of garden trowels, SciTechDaily reports.

 

The fossils of this duck-billed dino have provided striking new evidence
Aquilarhinus lived in what is now Big Bend National Park, in Texas, around 80 million years ago. Illustration by ICRA Art via SciTechNews.

But the fossils have actually been sitting on shelves since the 1980s

 

The big beast was unearthed by paleontologists at Big Bend National Park, in southwestern Texas but wasn’t analyzed until recently, LiveScience reports. For the most part, Aquilarhinus resembles your typical duck-billed dinosaur, but apparently without the fancy crest sported by some of these remarkable creatures.

 

Like Parasaurolophus, for instance…

 

Duck-billed dinos like Parasaurolophus had fascinating features
Parasaurolophus definitely has a magnificent crest. Illustration by Steveoc 86, license CC 2.5 via Wikimedia Commons

Lambeosaurus…

 

The crests of duck-billed dinos were very diverse
Lambeosaurus magnicristatus. Illustration by Участник:ДиБгд, license: Public Domain via Wikimedia Commons

And Tsintaosaurus

 

We have much to learn about hadrosaurs
Tsintaosaurus spinorhinus. Illustration by Nobu Tamura, license CC SA 3.0 via Wikimedia Commons

As you can see, Aquilarhinus shares some features with its duck-billed homies in the group Saurolophidae. However, it was more primitive and gives scientists a glimpse of how these fascinating crests evolved. Their findings were published in the Journal of Systematic Paleontology.  Like many dinosaurs, this one has an evocative name that means “eagle-nose shove-chinned” and combines the Latin word “Aquila” and the Greek word “rhinos” (nose.)

 

Like it’s colleagues above, Aquilarhinus is in the hadrosaurid group, dinosaurs that typically have beak-like jaws that widen at the end into a scoop shape.

 

“Hence the nickname ‘duck-billed dinosaurs'” said lead study author Alberto Prieto-Márquez, a researcher at the Catalan Institute of Palaeontology Miquel Crusafont in Barcelona, Spain.

But there is one key difference between Aquilasaurus and other hadrosaurs.

 

“However, they differ from Aquilarhinus in that this scoop is all concave,” Prieto-Márquez said in an email to LiveScience. “In contrast, in Aquilarhinus, there was a rise, a convex relief at the center of the ‘scoop.'”

Dinosaur fossils abound in this park
Big Bend National Park, in southwestern Texas, was once filled with swamps where duck-billed dinosaurs roamed. Photo by BFS Man, license CC 2.0 via Flickr

In the land before time

 

While Big Bend is largely Chihuahuan desert these days, 80 million years ago, when Aquilarhinus called this place home it was a land of marshes and swamps — perfect for a dino with a ridged, scooping chin. In their study, the researchers noted they believe the dinosaur used its uniquely scoop-like jaw to shovel plants from the muddy bottoms of creekbeds.

 

Duck-billed dinosaurs had complex teeth
Aquilarhinus’s unique lower jaw. The fossil is housed at the University of Texas at Austin. Screen capture by Alberto Prieto-Márquez via LiveScience

 

The scientists are still trying to figure out what the dinosaur’s prominent nasal crest was used for, however. They are leaning towards the idea that the crest helped these dinosaurs recognize each other and that it may have also been used to attract mates, Prieto-Márquez said.

 

“The crest of Aquilarhinus is simpler in structure than most of the other hadrosaurids, except for members of kritosaurini (a hadrosaurid subgroup),” he said. “In both Aquilorhinus and kritosaurins for which the crest is known, this is just a fold of the nasal bone, giving them a Roman nose appearance.”

In previous years, when other paleontologists studied the fossils, they thought the nasal crest resembled that of another hadrosaur, Gryposaurus. But the more they researched, the more they realized that Aquilarhinus was a more primitive hadrosaurid, and that placed it very near the base of the hadrosaurine family tree. And it suggested the diverse shapes of these cranial crests rose from a structure that began as a simple, arched nose, Prieto-Márquez said.

 

What’s also really cool about this discovery is that it also fills in part of the puzzle about the origins of these dinosaurs. Hadrosaurs were widespread, roaming across Europe, Asia, North and South America, and Antarctica during the latter part of the Cretaceous (145 to 65 million years ago.) And now analysis of Aquilarhinus further supports the hypothesis that hadrosaurs likely originated in the southern part of North America, the study authors say.

 

The fossils of this particular Aquilarhinus are reasonably well-preserved and when the creature died 80 million years ago, some of its bones were washed downstream through tidal marshes and wedged in vegetation. When the tide visited twice daily deposited silt that built up in the channel formed around its body and over time the fossils turned into ironstone. Which then, millions of years later, became a spectacular find for paleontologists.

 

Hadrosaurs came in a range of sizes, but most were definitely huge. So far, the largest known is Shantungosaurus giganteus, which was a staggering 15 meters (just over 49 feet) in length. Weighing 16 metric tons, this massive dinosaur lived in China.

 

In the videos below you can find out what Parasaurolophus sounded like and learn more interesting facts about dinosaurs.

 

Featured illustration by ICRA Art via LiveScience.

 


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